“No, no bread is being baked here today,” Christoph Winkelbauer clarifies right at the beginning. And the whole thing has nothing to do with pottery either. The word has not lost a “B” at the beginning – what he is building on this sunny afternoon together with colleagues in the Keltendorf am Kulm is really called “Rennofen”.
But from the beginning: Winkelbauer is a qualified locksmith and works as a teacher at the state vocational school 1 for metal technology in Graz. A few years ago, a newspaper advertisement aroused his interest: people were wanted to meet in Germany and build kilns together. “I rounded up a few colleagues and packed the trunk with things that I thought I might need for this,” he recalls with a smile.
Iron for the Celts
And what is a Rennofen? “The kiln is the process by which iron was smelted up until the 18th century. The kiln got its name because the slag (note: mixture of substances; created during the extraction of metals) runs away from the bottom, instead of like in a modern blast furnace begins to swim to the top,” explains Winkelbauer.
Under the group name “Furnance Fortune Styria” (loosely translated: “Ofen Glück Steiermark”), Winkelbauer, together with his teaching colleagues Bernhard Wronski and Markus Hirt, made pilgrimages to meetings all over Europe to bring kilns into the world. “Twenty to thirty ovens are then created at one meeting,” says the native of Gersdorfer.
The builders were also active in the open-air museum in Stübing, and they had made an attempt in the Celtic village years ago. “At that time we built the oven outside on a meadow, but it broke during transport to the exhibition area.”
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Baptism of fire on July 30, 2022
But this time everything should go well. For a whole weekend, the gentlemen build their oven, tinker with materials and design. Now let the oven dry out. “We are very pleased to have received a new exhibit in the form of the Rennofen,” says Siegfried Gruber from Keltendorf, emphasizing: “The experiment was made possible by a grant from the state of Styria for museums.”
The furnace will officially go into operation on July 30, 2022 – a novelty thanks to the old technology: “We will try to produce iron here at the Kulm,” says Winkelbauer with anticipation.
What makes the Rennofen so fascinating? “Actually, you throw in all the ingredients and then iron comes out,” laughs Winkelbauer and adds, a little amazed himself: “That it’s even possible!”
Also: “Everyone in Europe builds their kilns differently,” he says. The men, who are all around 40 by the way, have planned a new experiment for today: They do without bricks – because they didn’t exist back then either – and build the kiln out of wickerwork and clay.
Since the hobbyist heart laughs
Markus Kummer from Dietersdorf am Gnasbach (south-eastern Styria) is slapping this on the half-finished stove. He is a computer scientist and, like Georg Stocker from Graz, is taking part for the first time. “I’m a hobbyist. I like building something,” he explains his motivation. His goal: one day to be able to process something from self-made metal in his in-house forge.
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Winkelbauer also likes the idea of a circular economy: “The ingredients for iron production should be as regional as possible.” He got the iron ore from Burgenland, he says and proudly holds up a glass with a sample of it. Right next to it is a jar with solidified slag. If everything goes according to plan, visitors will soon be able to see for themselves how such materials are made.
Incidentally, Winkelbauer was not quite right about one point: Bread was still baked in the Celtic village that weekend – even if it was bread on a stick over a campfire.
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